1. Field of the Invention
This invention relates generally to semiconductor manufacturing, and, more particularly, to a method and apparatus for a dynamic targeting system for dynamically adjusting a process control system.
2. Description of the Related Art
The technology explosion in the manufacturing industry has resulted in many new and innovative manufacturing processes. Today""s manufacturing processes, particularly semiconductor manufacturing processes, call for a large number of important steps. These process steps are usually vital, and therefore, require a number of inputs that are generally fine-tuned to maintain proper manufacturing control.
The manufacture of semiconductor devices requires a number of discrete process steps to create a packaged semiconductor device from raw semiconductor material. The various processes, from the initial growth of the semiconductor material, the slicing of the semiconductor crystal into individual wafers, the fabrication stages (etching, doping, ion implanting, or the like), to the packaging and final testing of the completed device, are so different from one another and specialized that the processes may be performed in different manufacturing locations that contain different control schemes.
Generally, a set of processing steps is performed across a group of semiconductor wafers, sometimes referred to as a lot. For example, a process layer that may be composed of a variety of different materials may be formed across a semiconductor wafer. Thereafter, a patterned layer of photoresist may be formed across the process layer using known photolithography techniques. Typically, an etch process is then performed across the process layer using the patterned layer of photoresist as a mask. This etching process results in the formation of various features or objects in the process layer. Such features may be used as, for example, a gate electrode structure for transistors. Many times, trench isolation structures are also formed across the substrate of the semiconductor wafer to isolate electrical areas across a semiconductor wafer. One example of an isolation structure that can be used is a shallow trench isolation (STI) structure.
The manufacturing tools within a semiconductor manufacturing facility typically communicate with a manufacturing framework or a network of processing modules. Each manufacturing tool is generally connected to an equipment interface. The equipment interface is connected to a machine interface to which a manufacturing network is connected, thereby facilitating communications between the manufacturing tool and the manufacturing framework. The machine interface can generally be part of an advanced process control (APC) system. The APC system initiates a control script, which can be a software program that automatically retrieves the data needed to execute a manufacturing process.
FIG. 1 illustrates a typical semiconductor wafer 105. The semiconductor wafer 105 typically includes a plurality of individual semiconductor die 103 arranged in a grid 150. Using known photolithography processes and equipment, a patterned layer of photoresist may be formed across one or more process layers that are to be patterned. As part of the photolithography process, an exposure process is typically performed by a stepper on approximately one to four die 103 locations at a time, depending on the specific photomask employed. The patterned photoresist layer can be used as a mask during etching processes, wet or dry, performed on the underlying layer or layers of material, e.g., a layer of polysilicon, metal or insulating material, to transfer the desired pattern to the underlying layer. The patterned layer of photoresist is comprised of a plurality of features, e.g., line-type features or opening-type features that are to be replicated in an underlying process layer.
The health of a processing tool (tool health) may vary during wafer-processing performed by the processing tool. The tool health may relate to an assessment of how well the processing tool operates within a predetermined specification, which may include specifications such as tool environment characteristics (e.g., tool temperature, humidity, and the like) and quality and accuracy of the process performed by the processing tool. Variations in the tool health may occur and adversely affect the quality of processed semiconductor wafers 105. Variations in the tool health may cause degradation in the operation of a processing tool. A control model that is implemented to control the operation of the processing tool may be substantially modified to compensate for the degradation of operations of the processing tool. Eventually, the control model may become excessively modified, and as a result, the operation of the processing tool may become unpredictable and/or unreliable. In other words, the process operation may drift from a predetermined range of values. This may result in non-uniform quality and accuracy in the processed semiconductor wafers 105.
Turning now to FIG. 2, a typical flow of processes performed on a semiconductor wafer 105 by a semiconductor manufacturing system is illustrated. Generally, semiconductor wafers 105 are processed by a manufacturing system (block 210). Upon processing the semiconductor wafers 105, the manufacturing system may make a determination whether a scheduled time to acquire manufacturing data, such as metrology data, tool state data, and the like; or a triggering event (e.g., tool malfunction, etc.) that causes acquisition of manufacturing data, has occurred (block 220). When the system determines that a scheduled time or a triggering event to acquire manufacturing data has not occurred, the manufacturing system continues to process semiconductor wafers 105 (block 225).
When the manufacturing system determines that a triggering event or a scheduled time to acquire manufacturing data has occurred, acquisition of manufacturing-related data is performed (block 230). This may include acquiring metrology data related to the processed semiconductor wafers 105 and/or acquiring tool state data (e.g., pressure data, temperature data, humidity data, gas flow rate data, and the like). The manufacturing system may then perform an analysis of the acquired manufacturing related data to check for process errors, defects on the-processed semiconductor wafers 105, and the like (block 240). In response to the analysis of the manufacturing-related data, the manufacturing system may perform adjustments to subsequent process operations (block 250). Subsequently, the manufacturing system may continue processing semiconductor wafers 105 using the modified control model (block 260). Alternatively, the manufacturing system may stop processing semiconductor wafers 105 based upon the analysis of the manufacturing related data.
Among the problems associated with the current methodology include, having to wait to perform large amounts of analysis and/or computations to adjust process operations performed on the semiconductor wafers 105. Having to wait to perform these analysis and/or computations may slow down the rate at which adjustments to subsequent process operations are performed. For example, processing a large amount of manufacturing-related data to perform a run-to-run control may not be efficient since some calculations may require in-depth analysis and may be available too late to perform certain types of feedback or feed-forward adjustments. Additionally, performing wafer-to-wafer adjustments may be difficult since certain analysis of manufacturing data may not be available on a wafer-to-wafer basis.
Furthermore, current methodologies involve waiting for a scheduled time, such as the completion of the processing of a certain number of semiconductor wafers 105, before manufacturing-related data is acquired. Current methodologies may call for awaiting a triggering event, such as a catastrophic event during processing, or an interference performed manually by an operator, before manufacturing-related data is acquired. Manufacturing process adjustments are generally made based upon data acquired in response to scheduled intervals and/or triggering events. Therefore, an appreciable number of semiconductor wafers 105 may be processed using non-current manufacturing data. This may cause errors on the processed semiconductor wafers 105 that may otherwise be avoidable.
The present invention is directed to overcoming, or at least reducing, the effects of, one or more of the problems set forth above.
In one aspect of the present invention, a method is provided for performing dynamic targeting adjustments of a process control system. The method comprises performing a process step upon a first workpiece in a batch based upon a process target setting. The process target setting comprises at least one parameter relating to a target characteristic of the first workpiece. The method further comprises acquiring manufacturing data relating to processing of the first workpiece. The manufacturing data comprises at least one of a metrology data relating to the processed first workpiece and a tool state data relating to the tool state of a processing tool. The method further comprises acquiring electrical data relating to the processed first workpiece at least partially during processing of a second workpiece in the batch and adjusting dynamically the process target setting based upon a correlation of the electrical data with the manufacturing data.
In another aspect of the present invention, a method is provided for dynamically adjusting processing of semiconductor wafers, which comprises processing a semiconductor wafer based upon a process target setting relating to at least one of a yield, quality, and performance of the semiconductor wafer, acquiring metrology data relating to the processed semiconductor wafer based upon at least one of a scheduled interval and a triggering event and acquiring electrical data relating to the processed semiconductor wafer in an approximately real time manner during processing of the batch. The method provided for dynamically adjusting processing of semiconductor wafers further comprises adjusting dynamically the process target setting based upon analysis of the electrical data and the metrology data. The method provided for dynamically adjusting a targeting system for processing semiconductor wafers comprises processing a semiconductor wafer based upon a process target provided by the targeting system, acquiring manufacturing data related to the processed semiconductor wafer, the manufacturing data comprising at least one of a metrology data relating to the processed workpiece and a tool state data relating to a tool state of a processing tool and acquiring electrical data relating to the processed semiconductor wafer during processing of the batch. The method provided for dynamically adjusting a targeting system for processing semiconductor wafers further comprises dynamically adjusting said targeting system based upon said manufacturing data and said electrical data.
In another aspect of the present invention, a system is provided for dynamic targeting for a process control system. The system comprises a processing tool and a process controller operatively coupled to the processing tool. The processing tool processes a workpiece and the process controller performs a dynamic targeting analysis for targeting one or more parameters related to processing the workpiece. The dynamic targeting analysis comprises dynamically adjusting a process target setting related to the one or more parameters based upon an analysis of electrical data relating to the processed workpiece and metrology data related to the processed workpiece.
In yet another aspect of the present invention, a computer readable program storage device encoded with instructions is provided for performing dynamic targeting adjustments of a process control system. A computer readable program storage device encoded with instructions that, when executed by a computer, performs a method, which comprises performing a process step upon a first workpiece in a batch based upon a process target setting, the process target setting comprising at least one parameter relating to a target characteristic of the processed workpiece, acquiring manufacturing data relating to the processing of the workpiece, the manufacturing data comprising at least one of a metrology data relating to the processed workpiece and a tool state data relating to a tool state of a processing tool. The computer readable program storage device encoded with instructions that, when executed by a computer, further performs a method that provides acquiring electrical data relating to the processed first workpiece at least partially during processing of a second workpiece in batch and adjusting dynamically the process target setting based upon a correlation of the electrical data with the manufacturing data.